21. Apart from its mechanical properties , lead is also useful in lead acid batteries. 22. Arc welding reduces mechanical properties to no worse than O hardening condition. 23. It is primarily used to improve mechanical properties or reduce / eliminate distortion. 24. Their mechanical properties scale with relative density according to the geometry. 25. Mechanical properties of carbon nanotubes says a little more, not much.26. The density of a wood correlates with its strength ( mechanical properties ). 27. The resulting grain structure is circumferential, which gives better mechanical properties . 28. As with the previous mechanical properties , there are various ASTM methods for assessment. 29. Many natural ( or biological ) materials are complex composites with remarkable mechanical properties . 30. Cross-linked PTFE has improved high-temperature mechanical properties and radiation stability.